Λήψη αποφάσεων και ασαφής λογική

2020 ◽  
Author(s):  
Ελένη Βλάμου
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Vector Quantization ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Back Propagation ◽  
Fuzzy Inference Systems ◽  
Inference System ◽  
Neuro Fuzzy ◽  
Inference Systems

Η ασαφής λογική αποτελεί μια θεωρία της οποίας οι εφαρμογές έχουν σκοπό να παρέχουν βελτιωμένες λύσεις σε προβλήματα με υψηλό βαθμό αβεβαιότητας. Η θεωρία, η τεχνολογία και οι εφαρμογές της ασαφούς λογικής έχουν σημειώσει τα τελευταία χρόνια ταχύτατη ανάπτυξη και έχουν καταστεί αξιόπιστο και εύχρηστο εργαλείο σε πολλές επιστημονικές και ερευνητικές περιοχές. H παρούσα διατριβή εστιάζει στην κατανόηση των δομών της ασαφούς λογικής, και στην ανάλυση των ασαφών κανόνων και συστημάτων. Γίνεται μια ολοκληρωμένη παρουσίαση της θεωρίας ασαφών συνόλων με έμφαση στην κατανόηση των ασαφών συστημάτων (Fuzzy Inference Systems). Σκοπός είναι η ανάλυση της αποτελεσματικότητας της εφαρμογής της ασαφούς λογικής σε ποικίλα ασαφή συστήματα. Επιπλέον εστιάζει στην ανάδειξη της σπουδαιότητας της ασαφούς λογικής και των ασαφών συστημάτων λήψεως αποφάσεων, η χρήση των οποίων παρουσιάζει σημαντικά πλεονεκτήματα αναφορικά με την αποτελεσματικότητά τους. Ειδικότερα, η μίξη των τεχνητών νευρωνικών δικτύων και ασαφών συστημάτων επιτρέπει στους ερευνητές να διαμορφώνουν προβλήματα με την ανάπτυξη των έξυπνων και προσαρμοστικών συστημάτων. Έτσι γίνεται η περιγραφή του μοντέλου του ασαφούς νευρωνικού δικτύου και παρουσιάζονται εκπαιδευτικοί αλγόριθμοι (όπως ο Back-Propagation) που χρησιμοποιείται για τη βελτίωση της απόδοσης του δικτύου. Η βελτιωμένη αποδοτικότητα των εκπαιδευμένων ασαφών δικτύων επιβεβαιώνεται με την εφαρμογή και οπτικοποίηση του αλγορίθμου Back-Propagation στην Matlab. Επιπλέον γίνεται ανάλυση της εφαρμογής των ασαφών συστημάτων με σκοπό την αναγνώριση προτύπων και ανάλυση εγκεφαλογραφικού σήματος. Έτσι, γίνεται περιγραφή των γραμμικών μεθόδων αναγνώρισης προτύπων για την ανάλυση του σήματος του εγκέφαλου (όπως οι μετασχηματισμοί Fast Fourier transform, μετασχηματισμός Wavelet και μετασχηματισμός Vector Quantization) με σκοπό την προβολή της υπεροχής των ασαφών νευρωνικών δικτύων (SOMF), των συστημάτων ασαφών ταξινομητών και των ταξινομητών προσαρμοσμένων ασαφών νευρωνικών συστημάτων (ANFIS-Adaptive Neuro-Fuzzy Inference System). Επιπλέον, αναλύεται η εφαρμογή των ασαφών δικτύων αναφορικά με τη διάγνωση της επιδημιολογίας η οποία ενισχύεται με την παρουσίαση διαφορετικών επιδημιολογικών μοντέλων (όπως τα στοχαστικά επιδημιολογικά μοντέλα, π.χ. το μοντέλο SI και SIS, και τα ντετερμινιστικά επιδημιολογικά μοντέλα όπως το μοντέλο SIR) με σκοπό να αναδείξει την υπεροχή των ασαφών μεθόδων σε αυτήν την περίπτωση. Η περιγραφή των ασαφών μοντέλων SI και SIS αναδεικνύει την υπεροχή τους που ενισχύεται με την ανάλυση των ασαφών πιθανοτήτων για τη λήψη αποφάσεων στον τομέα της επιδημιολογίας. Επιπλέον, παρουσιάζεται η εφαρμογή των ασαφών συστημάτων σε θέματα βελτίωσης της απόδοσης των γενετικών αλγορίθμων. Γίνεται η ανάλυση των βασικών αρχών και χαρακτηριστικών των γενετικών αλγορίθμων, η περιγραφή των προσαρμοζόμενων πιθανοτήτων διέλευσης και μετάλλαξης και η ανάλυση των γενετικών παραγόντων που οδηγούν στην ανάπτυξη της εξέλιξης των αισθητήρων (EGP). Με αυτό τον τρόπο υποστηρίζεται η βελτιωμένη απόδοση και η αποτελεσματικότητα των ασαφών γενετικών αλγορίθμων.

scholarly journals Classification of EEG Signals using Fast Fourier Transform (FFT) and Adaptive Neuro Fuzzy Inference System (ANFIS)

2019 ◽  
Vol 5 (1) ◽  
pp. 35-44
Author(s):  
Suwanto Suwanto ◽  
M. Hasan Bisri ◽  
Dian Candra Rini Novitasari ◽  
Ahmad Hanif Asyhar
Keyword(s):  
Feature Extraction ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Eeg Signal ◽  
Eeg Signals ◽  
Inference System ◽  
Neuro Fuzzy ◽  
The Brain

Epilepsy is a disease that attacks the brain and results in seizures due to neurological disorders. The electrical activity of the brain recorded by the EEG signal test, because EEG test can be used to diagnose brain and mental diseases such as epilepsy. This study aims to identify whether a person has epilepsy or not along with the result of accurate, sensitivity, and precision rate using Fast Fourier Transform (FFT) and Adaptive Neuro-Fuzzy Inference System (ANFIS) method. The FFT is used to transform EEG signals from time-based into frequency-based and continued with feature extraction to take characteristics from each filtering signal using the median, mean, and standard deviations of each EEG signal. The results of the feature extraction used for input on the category process based on characteristics data (classification) using ANFIS. EEG signal data is obtained from epilepsy center online database of Bonn University, German. The results of the EEG signal classification system using ANFIS with two classes (Normal-Epilepsy) states accuracy, sensitivity, and precision of 100%. The classification systems with three class division (Normal-Not Seizure Epilepsy-Epilepsy) resulted in an accuracy of 89.33% sensitivity of 89.37% and precision of 89.33%.

scholarly journals A Proposal of an Adaptive Neuro-Fuzzy Inference System for Modeling Experimental Data in Manufacturing Engineering

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1390 ◽  
Author(s):  
C. J. Luis Pérez
Keyword(s):  
Fuzzy Inference System ◽  
Regression Models ◽  
Fuzzy Inference ◽  
Fuzzy Inference Systems ◽  
Inference System ◽  
Neuro Fuzzy ◽  
Regression Techniques ◽  
Inference Systems ◽  
Conventional Regression ◽  
Response Variables

In Manufacturing Engineering there is a need to be able to model the behavior of technological variables versus input parameters in order to predict their behavior in advance, so that it is possible to determine the levels of variation that lead to optimal values of the response variables to be obtained. In recent years, it has been a common practice to rely on regression techniques to carry out the above-mentioned task. However, such models are sometimes not accurate enough to predict the behavior of these response variables, especially when they have significant non-linearities. In this present study a comparative analysis between the precision of different techniques based on conventional regression and soft computing is initially carried out. Specifically, regression techniques, based on the response surface model, as well as the use of artificial neural networks and fuzzy inference systems along with adaptive neuro-fuzzy inference systems will be employed to predict the behavior of the aforementioned technological variables. It will be shown that when there are difficulties in predicting the response parameters by using regression models, soft computing models are highly effective, being much more efficient than conventional regression models. In addition, a new method is proposed in this study that consists of using an iterative process to obtain a fuzzy inference system from a design of experiments and then using an adaptive neuro-fuzzy inference system for tuning the constants of the membership functions. As will be shown, with this method it is possible to obtain improved results in the validation metrics. The means of selecting the membership functions to develop this model from the design of experiments is discussed in this present study in order to obtain an initial solution, which will be then tuned by using an adaptive neuro-fuzzy inference system, to predict the behavior of the response variables. Moreover, the obtained results will also be compared.

scholarly journals Prediction of littoral drift with Adaptive Neuro-Fuzzy Inference System

2010 ◽  
Vol 42 (1) ◽  
pp. 159-167
Author(s):  
Masumeh Sabet ◽  
Mehdi Naseri ◽  
Hosein Sabet
Keyword(s):  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Back Propagation ◽  
Linear Process ◽  
Back Propagation Algorithm ◽  
Littoral Drift ◽  
Inference System ◽  
The Past ◽  
Neuro Fuzzy ◽  
Sand Drift

Prediction of littoral drift with Adaptive Neuro-Fuzzy Inference System The amount of sand moving parallel to a coastline forms a prerequisite for many harbor design projects. Such information is currently obtained through various empirical formulae. Despite so many works in the past, an accurate and reliable estimation of the rate of sand drift has still remained a problem. It is a non-linear process and can be described by chaotic time-series. The current study addresses this issue through the use of Adaptive Neuro-Fuzzy Inference System (ANFIS). ANFIS is about taking an initial fuzzy inference system (FIS) and tuning it with a back propagation algorithm based on the collection of input-output data. ANFIS was developed to predict the sand drift from a variety of causative variables. The structure and algorithm of ANFIS for predicting the rate of sand drift is described. The Adaptive Neuro-Fuzzy Inference System was validated by confirming its consistency with a database of specified physical process.

Demand forecasting in the beauty industry using fuzzy inference systems

2020 ◽  
Vol 15 (4) ◽  
pp. 1389-1417
Author(s):  
Ricardo Felicio Souza ◽  
Peter Wanke ◽  
Henrique Correa
Keyword(s):  
Time Series ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Theory And Practice ◽  
Forecast Errors ◽  
Fuzzy Inference Systems ◽  
Inference System ◽  
Content Type ◽  
Forecasting Methods ◽  
Inference Systems

Purpose This study aims to analyze the performance of four different fuzzy inference system-based forecasting tools using a real case company. Design/methodology/approach The forecasting tools were tested using 27 products of the nail polish line of a multinational beauty company and the performance of said tools was compared to those of the company’s previous forecasting methods that were basically qualitative (informal and intuition-based). Findings The performance of the methods analyzed was compared by using mean absolute percentage error. It was possible to determine the characteristics and conditions that make each model the best for each situation. The main takeaways were that low kurtosis, negatively skewed demand time-series and longer horizon forecasts that favor the fuzzy inference system-based models. Besides, the results suggest that the fuzzy forecasting tools should be preferred for longer horizon forecasts over informal qualitative methods. Originality/value Notwithstanding the proposed hybrid modeling approach based on fuzzy inference systems, our research offers a relevant contribution to theory and practice by shedding light on the segmentation and selection of forecasting models, both in terms of time-series characteristics and forecasting horizon. The proposed fuzzy inference systems showed to be particularly useful not only when time-series distributions present no clear central tendency (that is, they are platykurtic or dispersed around a large plateau around the median, which is the characteristic of negative kurtosis), but also when mode values are greater than median values, which in turn are greater than mean values. This large tail to the left (negative skewness) is typical of successful products whose sales are ramping up in early stages of their life cycle. For these, fuzzy inference systems may help managers screen out forecast bias and, therefore, lower forecast errors. This behavior also occurs when managers deal with forecasts of longer horizons. The results suggest that further research on fuzzy inference systems hybrid approaches for forecasting should emphasize short-term forecasting by trying to better capture the “tribal” managerial knowledge instead of focusing on less dispersed and slower moving products, where the purely qualitative forecasting methods used by managers tend to perform better in terms of their accuracy.

Multilayer Optimization Approach for Fuzzy Systems

2011 ◽  
pp. 1121-1129
Author(s):  
Ivan N. Silva ◽  
Rogerio A. Flauzino
Keyword(s):  
Energy Function ◽  
Fuzzy Inference System ◽  
Mean Squared Error ◽  
Fuzzy Inference ◽  
Fuzzy Inference Systems ◽  
Energy Functions ◽  
Inference System ◽  
Squared Error ◽  
The Mean ◽  
Inference Systems

The design of fuzzy inference systems comes along with several decisions taken by the designers since is necessary to determine, in a coherent way, the number of membership functions for the inputs and outputs, and also the specification of the fuzzy rules set of the system, besides defining the strategies of rules aggregation and defuzzification of output sets. The need to develop systematic procedures to assist the designers has been wide because the trial and error technique is the unique often available (Figueiredo & Gomide, 1997). In general terms, for applications involving system identification and fuzzy modeling, it is convenient to use energy functions that express the error between the desired results and those provided by the fuzzy system. An example is the use of the mean squared error or normalized mean squared error as energy functions. In the context of systems identification, besides the mean squared error, data regularization indicators can be added to the energy function in order to improve the system response in presence of noises (from training data) (Guillaume, 2001). In the absence of a tuning set, such as happens in parameters adjustment of a process controller, the energy function can be defined by functions that consider the desired requirements of a particular design (Wan, Hirasawa, Hu & Murata, 2001), i.e., maximum overshoot signal, setting time, rise time, undamped natural frequency, etc. From this point of view, this article presents a new methodology based on error backpropagation for the adjustment of fuzzy inference systems, which can be then designed as a three layers model. Each one of these layers represents the tasks performed by the fuzzy inference system such as fuzzification, fuzzy rules inference and defuzzification. The adjustment procedure proposed in this article is performed through the adaptation of its free parameters, from each one of these layers, in order to minimize the energy function previously specified. In principle, the adjustment can be made layer by layer separately. The operational differences associated with each layer, where the parameters adjustment of a layer does not influence the performance of other, allow single adjustment of each layer. Thus, the routine of fuzzy inference system tuning acquires a larger flexibility when compared to the training process used in artificial neural networks. This methodology is interesting, not only for the results presented and obtained through computer simulations, but also for its generality concerning to the kind of fuzzy inference system used. Therefore, such methodology is expandable either to the Mandani architecture or also to that suggested by Takagi-Sugeno.

scholarly journals Missing Samples Estimation of Synthetic ECG Signals by FCM-based Adaptive Neuro-Fuzzy Inference System (FCMANFIS)

2021 ◽  
Author(s):  
asghar dabiri ◽  
Nader Jafarnia Dabanloo ◽  
Fereidoon Nooshirvan Rahatabad ◽  
Keivan Maghooli
Keyword(s):  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Back Propagation ◽  
Synthetic Data ◽  
Least Square ◽  
Inference System ◽  
Ecg Signals ◽  
Neuro Fuzzy ◽  
Fuzzy C Means Clustering ◽  
System File

Abstract This paper presents estimation of missed samples recovery of Synthetic electrocardiography (ECG) signals by an ANFIS (Adaptive neuro-fuzzy inference system) method. After designing the ANFIS model using FCM (Fuzzy C Means) clustering method. In MATLAB’s standard library for ANFIS, only least-square-estimation and the back-propagation algorithms are used for tuning membership functions and generation of fis (fuzzy inference system) file, but at current work we have used FCM method that shows better result. Root mean square error (difference of the reference input and the generated data by ANFIS) for the three synthetic data cases are: a. Train data: RMSE = 1.7112e-5b. Test data: RMSE = 5.184e-3c. All data: RMSE = 2.2663e-3

scholarly journals Comparative Study of Mamdani-type and Sugeno-type Fuzzy Inference Systems for Coupled Water Tank

2020 ◽  
Vol 3 (1) ◽  
pp. 42
Author(s):  
Halim Mudia
Keyword(s):  
Fuzzy Inference System ◽  
Chemical Engineering ◽  
Fuzzy Inference ◽  
Engineering System ◽  
Water Tank ◽  
Fuzzy Inference Systems ◽  
Process Industries ◽  
Inference System ◽  
Inference Systems ◽  
Level 2

The level and flow control in tanks are the heart of all chemical engineering system. The control of liquid level in tanks and flow between tanks is a basic problem in the process industries. Many times the liquids will be processed by chemical or mixing treatment in the tanks, but always the level of fluid in the tanks must be controlled and the flow between tanks must be regulated in presence of non-linearity. Threfore, in this paper will use fuzzy inference systems to control of  level 2 are developed using Mamdani-type and Sugeno-type fuzzy models. The outcome obtained by two fuzzy inference systems is evaluated. This paper summarizes the essential variation among the Mamdani-type and Sugeno-type fuzzy inference systems with setpoint of level is 10 centimeter. Matlab fuzzy logic toolbox is used for the simulation of both the models. This also confirms which one is a superior choice of the two fuzzy inference systems to control of level 2 in tank 2. The results show madani-type fuzzy inference system is superior as compared to sugeno-type fuzzy inference system.

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